Production of ketoximes



United States Patent PRODUCTION OF KETOXIMES Eugen Mueller and Dorla Fries, Tubingen, and Horst Metzger, Ludwigshafen (Rhine), Germany No Drawing. Application August 1, 1956 Serial No. 601,383

This invention relates to an improved process for the production of ketoximes. It relates more specifically to improvements in the production of ketoximes from saturated hydrocarbons.

In the co-pending application S.N. 496,946, filed March 25, 1955, by Eugen Mueller, Horst Metzger and Dorla Fries for Production of Ketoximes a process for the production of ketoximes has been described according to which a mixture of nitrogen monoxide and chlorine which contains the nitrogen monoxide in a large molecular excess as compared with the chlorine is allowed to act in the presence of light, preferably that of a wave length of 350 to 700 millimicrons, on a liquid saturated cycloaliphatic or aliphatic hydrocarbon, the bis-nitrosocyclohexane formed as the main product and the 1-chlor-1-nitrosocyclohexane formed as a by-product being converted into cyclohexanone oxime by heating or/and by irradiation. This earlier filed application describes suitable initial materials which can be converted to ketoximes as including the saturated alkanes and cycloalkanes containing from to 12 carbon atoms.

We have now found that the formation of bis-nitroso and l-chlor-l-nitroso compounds can be bypassed and ketoximes or their hydrochlorides can be directly obtained by allowing dry hydrogen chloride, chlorine and nitrogen monoxide to act simultaneously on normally liquid saturated aliphatic or cycloaliphatic hydrocarbons while irradiating them with active light.

It is preferable first to saturate the hydrocarbon to be oximated with dry hydrogen chloride and then to lead into it, while irradiating it, a mixture of chlorine and nitrogen monoxide with which hydrogen chloride is also advantageously admixed. The most favorable molar ratio of Cl :NO lies at about 1:3, but a smaller or greater molar ratio, for example between 1:8 and 2:1, may be used. The amount of hydrogen chloride to be added may vary within wide limits. If the hydrocarbon has been previously saturated with hydrogen chloride, it is not necessary to add hydrogen chloride to the mixture of chlorine and nitrogen monoxide or only a relatively small amount thereof need by added, for example to 30 percent, with reference to the amount of chlorine used. In other cases about 50 percent of dry hydrogen chloride, with reference to the amount of chlorine used, is added to the mixture of chlorine and nitrogen monoxide.

The result of the coemployment of hydrogen chloride may be seen in the fact that immediately after commencement of irradiation with active light, the corresponding oxime hydrochloride begins to separate in an oily or solid form without the bis-nitroso compounds being formed. The chlornitroso compounds and polychlor compounds which are formed as byproducts in the process according to the said application S.N. 496,946 are not formed in the present process or only occur in very small amounts; nitro compounds or nitric acid or nitrous acid esters are also formed at the most in traces. The oximes are set free from the hydrochlorides obtained best by dissolving the latter in water and neutralizing the aqueous solution,

for example with caustic alkali or ammonia solutions.

The following examples will further illustrate this invention but the invention is not restricted to these examples.

Example 1 240 grams of cyclohexane are saturated with dry hydrogen chloride and then a mixture of 750 ccs. of chlorine gas and 2,250 ccs. of nitrogen monoxide (with reference to normal conditions) is led in per hour at about 15 C. through a sieve plate, while irradiating with a mercury immersion lamp. It is advantageous to add to the gas mixture a further 200 ccs. of dry hydrogen chloride per hour so that the solution is continuously saturated with hydrogen chloride. After a short time an oil begins to separate which collects at the bottom of the reaction vessel and is run off from time to time. The oil is dissolved in water and neutralized with caustic soda solu tion, the cyclohexanone oxime thereby crystallizing out. By extraction of the cyclohexane layer with water and neutralization of the extract with caustic soda, further amounts of oxime are obtained. The total yield amounts to 6.2 to 6.5 grams of pale yellowish cyclohexanone oxime after 2% hours duration of the reaction.

Example 2 250 grams of cycle-octane are saturated at about 15 C. with dry hydrogen chloride and each hour there is led in through a sieve plate, while irradiating with a mercury immersion lamp, a mixture of 750 ccs. of chlorine and 2,250 ccs. of nitrogen monoxide to which preferably 200 ccs. of hydrogen chloride have been added so that the solution is continuously saturated with hydrogen chloride. At once the cyclo-octanone oxime hydrochloride begins to separate at the bottom of the vessel in crystalline form or as a viscous oil. By working up as in Example 1 there are obtained 13 grams of cyclooctanone oxime in all after 2 /2 hours duration of reaction.

Example 3 225 grams of n-heptane are charged into a reaction vessel and saturated therein with dry hydrogen chloride. Then a mixture of 690 ccs. of chlorine gas and 2,080 ccs. of nitrous oxide (with reference to normal conditions) is fed in per hour through a sieve plate at 20 C. and simultaneously exposed to the action of a mercury immersion lamp. Advantageously the feed of dry hydrogen chloride into the reactor is continued at a rate of 200 ccs. an hour in order to maintain constancy in the hydrogen chloride saturation of the solution. After a short time an oil commences to separate. It collects at the bottom from which it is run otf from time to time. The oil is dissolved in water and neutralized with caustic soda solution, a mixture of isomeric heptanone oximes being separated as an oil. By extracting the n-heptane with water, neutralizing the extract with caustic soda solution and further extracting the aqueous solutions with ether further quantities of an oxime mixture with a boiling point of 104 to 107 C. at a pressure of 19 millimeters Hg are obtained. The overall yield is 5.0 to 5.5 grams of oximes after a two and one-half hours duration of the reaction.

What we claim is:

1. An improved process for the production of ketoximes which comprises introducing a mixture of dry hydrogen chloride, nitrogen monoxide and chlorine in which the molar ratio Cl :NO lies between about 1:8 and 2:1 into a normally liquid saturated hydrocarbon while irradiating with active light, separating the oxime hydrochlorides formed and neutralizing them.

2. An improved process for the production of ketoximes which comprises saturating a normally liquid saturated hydrocarbon with dry hydrogen chloride, introwhich the molar ratio Cl :NO lies between about 1:8 and 2:1' while irradiating with active light, separating the oxim'e hydrochlorides formed and neutralizing them.

"3. 'An improved process for the production or cycloducing' a mixture of nitro en monoxide and chlorine in hexanone oxime which comprises saturating cyclohexane with dry hydrogen chloride, introducing a mixture o'f'dry I chlorine gas, nitrogen monoxide and hydrogen chloride in which the molar ratio (ll zNOzHCl is about 4:12: l at about 15 C. while irradiating with active light, separating the cyclohexanone hydrochloride formed and neutralizing it by means of a caustic alkali solution,

4. An improved 'process'for the production of cyclooctanone oxime which comprises saturating cyclooctane with dry hydrogen chloride, introducing a mixture of dry which the molar ratio C1 :NO':HCl is about 4:1221 at I about 15 C; while irradiating with active light, separating nitrogen monoxide and'chlorine in which, the molar ratio Cl :NO lies betweenabout 1:8 and 2:1 into a liquid saturated hydrocarbon selected from the group consisting I of alkanes and cycloalkanes'having from 5 to l2 carbon atoms while irradiating with activelight.

7. An improved process as claimed in claim 6 wherein I the hydrocarbon is cyclohexane,

chlorine gas, nitrogen monoxide and hydrogen chloride in I '8. An improved process as claimed in claim 6 wherein the hydrocarbon is cyclooctane. I

9. An improved process as claimed in claim 6 wherein Y the hydrocarbon is, n-heptane.

the cyelooctanone' oxime hydrochloride formed and new I tralizing it by means of a caustic alkali solution.

5'. An improved process for the production of a mixture of isomeric heptanone oximes which comprises saturating I n-heptane with dry hydrogen chloride, introducing a mixture of dry chlorine gas, nitrogen monoxide and hydrogen chloride in which the molar ratio CI CNOiI-ICl is about ReferencesCite dvin the file of this patent FOREIGN PATENTS 'REFERENCES Chemical Reviews, vol. 48 (1951 page 324. 

1. AN IMPROVED PROCESS FOR THE PRODUCTION OF KETOXIMES WHICH COMPRISES INTRODUCING A MIXTURE OF DRY HYDROGEN CHLORIDE, NITROGEN MONOXIDE AND CHLORINE IN WHICH THE MOLAR RATIO CL2:NO LIES BETWEEN ABOUT 1:8 AND 2:1 INTO A NORMALLY LIQUID SATURATED HYDROCARBON WHILE IRRADIATING WITH ACTIVE LIGHT, SEPARATING THE OXIME HYDROCHLORIDES FORMED AND NEUTRALIZING THEM. 